High speed printing apparatus



Aug. 4, 1959 G. v. A. MALMROS ETAL 2,897,752

HIGH SPEED PRINTING APPARATUS Filed Dec. 28, 1956 2 Sheets-Sheet 1 vINVENTORS RICHARD H. HARRINGTON a Y GUSTAV \l A. MALMROS their ATTORNEYSAug. 4, 1959 G. v. A. MALMROS ET AL 2,897,752

HIGH SPEEDPRINTING APPARATUS Filed Dec. 28, 1 956 2 Sheets-Sheet 2lllllllllllllllllllllllllli ii llllIllllllllllllllllll INVENTORS RICHARDH. HARRINGTON 8| GUSTAV V. A. MALMROS I BY their ATTORNEYS United StatesPatent Ofiice 2,897,752 Patented Aug. 4, 1959 2,897,752 HIGH SPEEDPRINTING APPARATUS Application December 28, 1956, Serial No. 631,168 7Claims. (Cl. 10193) This invention relates to a high speed printer and,more particularly, to such printers in which a number of the printingelements are in continuous motion.

Translating computed data from electrical signals to printed charactershas been one important factor limiting computer speeds. Among theproposed high speed printers, those having continuously moving printingelements, often termed on-the-fly printers, have many advantages. Forexample, continuously rotating type wheels or drums may cooperate withselectively actuated hammers to provide rapid printing, a number ofthese hammers ordinarily being laterally disposed to print lines ofcharacters. It is apparent that-the several printing hammers, one foreach column, must be closely synchronized in their actuation to precludefaulty alignment of the printed characters.

Previous printers of this type have included solenoid hammer actuators.However, electrical timing variations due to changes in supply voltagesand other factors resulted in objectionable misalignment of the printedlines.

An on-the-fly printer providing rapid and accurate printing has beendisclosed and claimed in copending application Serial No. 630,817, filedDecember 27, 1956, for High Speed Printer/f and it is an object of thepresent invention to provide an improved on-the-fly' high speed printer.

It is another object of the present invention to provide an improvedhigh speed printer in which the printed characters are accuratelyaligned.

It is a further object or": the invention to provide a printer of theabove character in which continuously moving character carrying elementsare synchronized with actuating hammers to provide accurately printedlines;

It is still another object of the invention to provide a printer havingthe above characteristics in which a firing pin cooperating with arotating type Wheel is selectively displaced into the path of actuatinghammers to print characters with a minimum of deviation from atheoretically correct timing arrangement.

These and further objects of the invention are accomplished by disposinga firing pin adjacent to a continuously rotating type wheel. A pluralityof hammers rotating synchronously with the type wheel normally pass theend of the firing pin; Upon reception of an actuating impulse, thefiring'pinis moved momentarily into the path of the hammers and therebydriven against a selected character on the type wheel to print it onsuitably positioned data receiving means.

These and further objects and advantages of the present invention willbe more readily understood when the following description is read inconnection with the accompanying drawings, in which:

Figure 1 is an elevation, partially broken away, of one printing stationof a high speed printer embodying the principles of the presentinvention; and

Figure 2 is a plan view of a plurality of the printing stationsillustrated in Figure 1 showing synchronized driving elements in thesystem.

Referring to a typical embodiment of the invention in greater detailwith particular reference to Figures 1 and 2, suitable supportingstructure for a high speed printer includes outer frame members 9between which are disposed type wheels 10, each carrying a completearray of fortyeight characters 11, rotated by a shaft 12 journaled inthe members 9. A pulley 13 on one end of the shaft 12 is driven by abelt 14 looped around a drive pulley 15 on a driving motor 16.

Pulleys 17 and 18 guide inked ribbon 19 and cooperating pairs of driverolls 20-21 and 22-23 control the movement of a continuous paper sheet24 in front of the type wheels 10. Any conventional ribbon and paperdrive may be substituted for this arrangement.

A firing pin 25 at each of the printing stations includes an enlargedhead portion 26 forming a shoulder 26a normally engaging a bushing 27formed of nylon, for example, in a carrier 28. A further bushing 29,also formed of nylon, is positioned at the other end of the carrier 28to guide the pin toward the type wheel 10. A wire spring -30 secured toan anchor 31 urges the pin 25 into the carrier 28 and holds the shoulder26a against the bushing 27. The carrier 28 pivots on a pin 32 betweenstops 33 and 34, as shown in phantom outline in Figure 1, a spring 35anchored by a pin 35a normally biasing the carrier against the stop 33.

A pull rod 36, formed with an angled end received in an opening 36a inthe carrier 28, is guided by a pair of offset pulleys 37 and 38. Aninsulated U-shaped connector 39 on the end of the rod 36 receives aterminal block 41 carried by the end of a tempered steel band 41, apin42 holding the connector and block together.

An electrostatic clutch 43 includes a continuously rotating drum 44driven by a shaft 45, a clutch facing layer 46 formed, for example, of ahard rubber and carbon composition, and the clutch band 41. The rightend of the clutch band 41 is urged upwardly by a spring 47 secured to ananchor 48, a conductor 49 supplying electrical impulses to energize theclutch.

The fast acting properties of electrostatic clutches are well known inthe art making it unnecessary to discuss the theory of such clutches indetail herein. In the present apparatus, the drum 44 and the surfacelayer 46 extend the length of the printing apparatus past the severalprinting stations, a separate clutch band 41 at each printing stationoperating the rods 36 and the firing pin carriers 28.

The clutch layer 46 is grounded through its hub 44 and shaft 45 and theclutch bands 41 are insulated by the connectors 39 and anchor 43.Accordingly, when a voltage pulse is applied to the band 41 through theconductor 49 and spring 47, the clutch band will be attracted to thesurface 46 of the continuously rotating clutch drum 44 and pulled in acounterclockwise direction, thereby operating the carrier 29. It will beevident that other fast acting clutches or similar mechanicalarrangements may be substituted for the electrostatic clutch 43.

A rotor 50 at each printing station is driven by a shaft 51 journaled inthe members 9'. A gear 52 on the shaft 51 meshes with an idler gear 53driven by a gear-54 on the shaft 12, the gear ratio being chosen todrive the rotor 50 at a speed several times that of the shaft 12, inthis particular example a ratio of four to one.

The rotor 56 carries twelve spaced hammers 55 pivoted on pins 56 andnormally resting against for-Ward stop pins 57. In order to transfermaximum energy between the hammer 55 and the firing pin 25, a strikingface 55a on each of the hammers 55 slants rearwardly to afford asubstantially perpendicular relationship between these elements. It willbe apparent that with the provision of twelve hammers on the rotor 50,forty-eight characters on the type wheel 10, and a four to one speedratio, during each rotation of the type wheel one of the ham mers 55will be in a position to strike the firing pin and print a selectedcharacter, as discussed hereinafter.

In a typical operation of the above described apparatus in accordancewith a cycle conventional to many on-thefly printers, such cycle may beconsidered as beginning with a 16 millisecond period devoted to paperspacing and the loading into storage of data for printing. Followingthis period, there are forty-eight cycle points each one of which isdevoted to the possible printing of one of the characters on the typewheel 10. For example, in order to print a series of lines at a 750'lines per minute rate, each cycle point is allocated a period of 1.4milliseconds so that the total cycle consists of 67.2 milliseconds forprinting and an additional 16 milliseconds for line spacing, the totalbeing 83.2 milliseconds per line.

A voltage pulse applied to the conductor 49 at a selected time shiftsthe carrier 28 from its initial attitude against the stop 33 to anoperative attitude against the pin 34 momentarily to shift the end ofthe firing pin protruding from the carrier into the path of one of thehammers 55 very rapidly, for example in 800 microseconds. The voltagepulse may be so timed that it terminates at the instant one of thehammers 55 strikes the end of the firing pin 25.

The effective mass of the hammers 55 preferably closely approximates themass of the firing pin 25. Under these circumstances the kinetic energyof the hammer 55 is transferred by impact to the firing pin 25 whichmoves forward with a high velocity carrying with it the paper 24 and theribbon 19 against the selected character 11 on the type wheel 10. Thefiring pin 25 then rebounds from the wheel 10 but is effectivelyrestrained from further action by the spring 30. After impact, thehammer moves in a clockwise direction around its pivot pin 56 and aftera short interval again assumes a position against the forward stop 57under the influence of centrifugal force. The carrier 28 is returned toits initial position by the spring 35 when the voltage pulse on theconductor 49 subsides.

When utilizing the above described high speed printer, it will beunderstood that timing of the firing pin is primarily a function of themechanical connection between the type Wheel 10 and the rotor 50 and,therefore, alignment of printed data on the paper 24 is dependent onlyupon the degree to which this mechanical synchronization is achieved.With precision gears, it will be obvious that such synchronization maybe within close tolerances.

It will be understood that the above-described embodiment of theinvention is illustrative only and modifications thereof will occur tothose skilled in the art. Therefore, the invention is not to be limitedto the particular apparatus described herein but is to be defined by theappended claims.

We claim:

1. In a high speed printer, a rotating type wheel having a plurality ofcharacters spaced along its periphery, a rotating element synchronizedwith the type wheel, a plurality of hammers pivoted on the rotatingelement and carried along a circular path, a firing pin assemblyincluding a firing pin slidably mounted in a movable carrier resilientlybiased to a position in which one end of the pin is adjacent to the typeWheel and its other end is adjacent to the circular path, the firing pinbeing adapted to urge data receiving means against the characters, andmeans to shift the carrier and place the other end of the firing pin inthe circular path at a selected time to receive a hammer blow and printa selected character on the data receiving means.

2. In a high speed printer, a rotating type wheel having a plurality ofcharacters spaced along its periphery, a rotating element synchronizedwith the type wheel, a plurality of hammers pivoted on the rotatingelement and carried along a circular path, a firing pin assembly in- Icluding a firing pin slidably mounted in a pivoted carrier resilientlybiased to a position in which one end of the pin is adjacent to the typewheel and its other end is adjacent to the circular path, the firing pinbeing adapted to urge data receiving means against the characters, meansresiliently urging the firing pin away from the type Wheel into thecarrier, and means to shift the carrier and place the other end of thefiring pin in the circular path at a selected time to receive a hammerblow and print a selected character on the data receiving means.

3. In a high speed printer, a rotating type wheel having a plurality ofcharacters spaced along its periphery, a rotating element synchronizedwith the type wheel, a plurality of hammers pivoted on the rotatingelement and carried along a circular path, a firing pin assemblyincluding a firing pin slidably mounted in a pivoted carrier resilientlybiased to a position in which one end of the pin is adjacent to the typewheel and its other end is adjacent to the circular path, the firing pinbeing adapted to urge data receiving means against the characters, andelectrostatic clutch means to shift the carrier and place the other endof the firing pin in the circular path at a selected time to receive ahammer blow and print a selected character on the data receiving means.

4. In a high speed printer, a rotating type wheel having a plurality ofcharacters spaced along its periphery, a rotating element synchronizedwith the type wheel, a plurality of hammers pivoted on the rotatingelement and carried along a circular path, a firing pin assemblyincluding a firing pin slidably mounted in a pivoted carrier resilientlybiased to a position in which one end of the pin is adjacent to the typewheel and its other end is adjacent to the circular path, meansresiliently urging the firing pin away from the type wheel and into thecarrier, the firing pin being adapted to urge data receiving meansagainst the characters, and electrostatic clutch means to shift thecarrier and place the other end of the firing pin in the circular pathat a selected time to receive a hammer blow and print a selectedcharacter on the data receiving means.

5. In a high speed printer, a member rotating a plurality of charactersalong an annular path, a firing pin adjacent to a printing location onthe annular path and adapted to urge data receiving means against thecharacters to print them, a movable carrier slidably mounting the firingpin with its rear end protruding from the carrier and further from theprinting location than its front end, a rotating element synchronizedwith said member, a plurality of hammers pivoted on the rotating elementand carried along a circular path, the movable carrier when in a firstattitude holding the firing pin away from a position normal to a tangentto the annular path at the printing location, the rear end of the firingpin in the first attitude being displaced from the circular path out ofcontact with the hammers, and means to shift the carrier momentarilyfrom its first attitude to a second attitude to dispose the firing pinnormal to the annular path tangent with the protruding rear end of thefiring pin in position to be struck by one of the hammers and drivenforward in the carrier to print with its front end a selected characteron the data receiving means, the firing pin rebounding after printingthe selected character, and means to retain the rebounded firing pin inits initial position with its rear end protruding from the carrier readyto be struck again and driven forward by one of the hammers.

6. In a high speed printer, a member rotating a plurality of charactersalong an annular path, a firing pin adjacent to a printing location onthe annular path and adapted to urge data receiving means against thecharacters to print them, a movable carrier slidably mounting the firingpin with its rear end protruding from the carrier and further from theprinting location than its front end, a rotating element synchronizedwith said member, a plurality of hammers pivoted on the rotating elementand carried along a circular path, the movable carrier when in a firstattitude holding the firing pin away from a position normal to a tangentto the annular path at the printing location, the rear end of the firingpin in the first attitude being displaced from the circular path out ofcontact with the hammers, and clutch means to shift the carriermomentarily from its first attitude to a second attitude to dispose thefiring pin normal to the annular path tangent with the protruding rearend of the firing pin in position to be struck by one of the hammers anddriven forward in the carrier to print with its front end a selectedcharacter on the data receiving means, the firing pin rebounding afterprinting the selected character, and means to retain the reboundedfiring pin in its initial position with its rear end protruding from thecarrier ready to be struck again and driven forward by one of thehammers.

7. In a high speed printer, a member rotating a plurality of charactersalong an annular path, a firing pin adjacent to a printing location onthe annular path and adapted to urge data receiving means against thecharacters to print them, a movable carrier slidably mounting the firingpin with its rear end protruding from the carrier and further from theprinting location than its front end, a rotating element synchronizedwith said member, a plurality of hammers pivoted on the rotating elementand carried along a circular path, the movable carrier when in a firstattitude holding the firing pin away from a position normal to a tangentto the annular path at the printing location, the rear end of the firingpin in the first attitude being displaced from the circular path out ofcontact with the hammers, and electrostatic clutch means to shift thecarrier momentarily from its first attitude to a second attitude todispose the firing pin normal to the annular path tangent with theprotruding rear end of the firing pin in position to be struck by one ofthe hammers and driven forward in the carrier to print with its frontend a selected character on the data receiving means, the firing pinrebounding after printing the selected character, and means to retainthe rebounded firing pin in its initial position with its rear endprotruding from the carrier ready to be struck again and driven forwardby one of the hammers.

References Cited in the file of this patent UNITED STATES PATENTS1,896,538 Bryce Feb. 7, 1933 1,981,990 Carroll Nov. 27, 1934 2,053,063Bryce Sept. 1, 1936 2,627,807 Buhler Feb. 10, 1953 2,766,686 Fomenko etal. Oct. 16, 1956 2,787,210 Shepard Apr. 2, 1957

